Overfalls
by AmiThePanda
Summary: (Might change title later). The barrier around Mt. Ebott is gone. Frisk and the population of the Underground are ready to greet the light of the surface; they weren't ready, however, for the mysteries that would unravel in the little town of Gravity Falls. How will both monsters and humans deal with this new life? Read on to find out! (no specific pairings, btw).
1. Prologue

**Heya! Before we start I just want to say: this is my first crossover and my first story without an OC. I'll be honest: I'm complete Undertale Trash and have been for quite a few months now... and now I'm slowly sinking deeper into the unique (and bottomless) pit that is the fandom of Gravity Falls! Yeah, it was about a week and a half ago that I watched and finished GF for the first time and... yes, I cried at the last two episodes, YOU GOT A PROBLEM WITH THAT?!... ahem... in any case! I was just sitting here, thinking of ideas on something to write involving one thing or the other when suddenly I thought:** _"Hey, why not a story with both?"_ **... and thus, here it is! xD**

 **I've only seen two or three crossovers involving a post-pacifist story, in which the monsters of the Underground go to the surface and find themselves in the curious little town of Gravity Falls. So I thought it would be great to write one of my own! This _prologue_ is just to give you a little insight on the situation Underground. A bit of backstory on one side of this story and an ending that will lead to the main plot.**

 **Also, I'm referring to Frisk as _'they'_ for now, to keep up the ambiguity of their gender until one of the next chapters (don't ask why, just go with it).**

 **Please enjoy~!**

"Normal dialog"  
 _'A character's thoughts'_

* * *

 **Prologue**

They had done it. They had _finally_ done it. Frisk won, and with Asriel's help, the barrier was broken.

Everyone in the Underground was happy! Asgore Dreemurr, that fuzzy pushover that was king of all monsters, called every monster to celebrate the little human's victory. For the sake of the celebration, Toriel tried her best to tolerate being near Asgore; Undyne and Alphys were spending quality time together; Mettaton (with his _now_ fully-functional body) dragged Napstablook along, who for the first time in a long while seemed so happy; Papyrus offered to cook some of his special spaghetti… of course, for everyone's wellbeing, Sans decided to distract him to take his mind off of his cooking plan.

And speaking of the comic, Sans was smiling a genuine grin this time; so far, the human hasn't restarted the timeline yet. That alone seemed like a good sign. Just a timeline ago, him and Frisk had a problem with a corrupted entity hell-bent on destroying everything and everyone. After hours and hours of research, Sans found a solution and got Frisk (the small part that was left of them, at least) to cooperate. Eventually, Chara left Frisk's body and disappeared off to God-knows-where.

Right now, Sans was sitting off to the side, smiling as he watched his brother interact with the others (and enjoying the attention the little Monster Kid was giving him). As he looked around, he noticed the center of the party was missing. From the corner of his eye-sockets, he saw a blue and magenta blur passing through the door. His sockets narrowed in confusion and, once he was sure no one was watching, teleported himself at the end of the Hall.

* * *

Ah, the Judgment Hall. This place brought a lot of memories for Frisk; some were good… the other 358 times, however, were the most frustrating and heart-wrenching moments they've ever lived. And that's saying something from the one who decided to run away from the orphanage that raised them.

Indeed, little Frisk was an orphan since they were 6 years old. The blurry memories they have before arriving to the orphanage are those of a loving mother and father who loved their sweet and silent child with all of their hearts. Everything was going well for the small family, until their car got crashed on their way to the small town of Ebott at the base of the mountain. Both mother and father didn't make it, and Frisk secluded themselves from the rest of the children.

Ever since then, most of the kids of the orphanage either ignore Frisk's existence or bully the silent child. One day, Frisk decided enough was enough and ran off to the mysterious Mount Ebott. Regardless of what happened to them, Frisk knew it would be better than living in that hellish place.

And now, here they were: countless of resets later, leaving the celebration of a pacific victory... walking through the one place that still brings them a certain sense of dread. Now, Frisk was happy, and everyone else was happy… but they felt like they didn't deserve it. There was only _one_ person left to save… maybe there was no way to save _him_ , but there's nothing to lose with just trying, right?

Frisk was already halfway through the hall, when the air shifted in front of them.

"heya, kid" Sans was smiling as usual, but his eye-sockets held a light of concern. "i noticed you were leaving, and i decided to come along with 'ya. y'know, so you don't feel _bonely_ " Frisk giggled and that sound helped to calm Sans' non-existent nerves.

"I'm okay, Sans" assured the quiet voice of his small friend.

"good to know, kiddo" Sans looked around the room, sockets slowing when he glanced at the windows letting the twilight shine through. "y'know, it's a bit _humerus_ , but what little i remember of us standing here, we're in swapped places" Sans seemed to breath in and out slowly (how does he do that?! _'Magic'_ , he says), closing his sockets, soaking in the calm and quiet. "… but this time… i feel at peace. of course, there's still a chance for you to reset everything, and we'll do this all over again, but still…" he was cut off at the sound of small steps getting closer.

"Sans, I told you before…" Sans tensed up at the feeling of thin arms around him, before he returned the hug tightly. "This one's the last. I promise you, this is the one. When the party's over, and after we have slept some hours, we're all gonna watch the sunrise! Just wait 'till you see it, it's _beautiful_!" the kid explained, moving their arms to emphasize their excitement.

Sans chuckled. Seeing Frisk's seriousness melting away to show their happier, more childlike side… it just made him smile no matter the circumstances.

"heh, just be sure to wake me up just in time to see it, ok?"

Frisk simply gave him a thumbs up before hugging him again and walking further away from the party.

"so, where 'ya goin', buddy?"

"…" Frisk thought carefully their next words "It's just… there's someone else I want to help"

"oh? mind if i tag along, kid? _tibia-nest_ i just wanna keep you company"

"Well…" the little brunette trailed off when an idea came. "Oh! Can you take us to the Ruins? I just want to get something from mom's house and then go talk to someone at the end of the cave"

"ok. hold on tight, kiddo; we're taking a shortcut" Frisk closed their eyes and Sans immediately got them inside the Ruins, in front of a tree just hiding Toriel's house from view. "so here's where tori lives? seems pretty cozy"

Frisk nodded happily. "I'll be right back!" they sprinted to the small house and searched through the few things left behind for the item she was searching.

Meanwhile, Sans was waiting outside, leaning on the bark of the tree while lazily twirling a small bone in his hand. He looked up when he heard the child's footsteps.

"that was fast…" he trailed off when he saw the item. "… uh, kid, why do you need an empty flower pot?" Frisk just smiled and tugged at Sans' sleeves to a certain path. "ok ok, i'm coming frisk" he chuckled and followed the energetic human.

Walking the long way, they arrived to the end of the cave. The rocky walls were humid; the floor was filled with grass, vines, and golden flowers growing all over the place. The most eye-catching spot was the center of the clearing, where a perfectly shaped flower bed was illuminated by the moonlight shining through the big hole at the ceiling of the cave (which served to tell Sans all of the time they took… _'Paps must be really worried right now…'_ ). That wasn't the only thing; over the rest of the flowers, stood a taller one with a familiar face watching them approaching.

"Oh, what a surprise! But if it isn't the _idiot_ and the _smiling trashbag_!" Flowey sneered at them.

"heh, nice to see you're doing well, weed. why do 'ya have that look on your face? did your parents _ground_ you?"

Flowey cringed. "Ugh, don't start with the bad jokes! Hey Frisk, just be quick and tell me what the heck do you want?"

Frisk smiled and showed him the pot they brought. "I'm not leaving you behind. You know that, right?"

Flowey looked genuinely shocked. "What?! But… after everything I did?... Even after I already told you there's nothing you can do for me?!" Flowey looked angry and… desperate. He _knew_ there was no way for him to be his old self again, and he didn't want his parents to know, but…

Sans was startled at the sight of the flower crying.

"I-I don't want to be alone anymore... why?... how am I feeling anything right now?!" he was confused, angry, sad, and a lot more at the same time.

"I'll take you with me! You won't be alone anymore… Asriel, I promise…" Flowey looked up with teary and hopeful eyes.

For Sans, the next few minutes were a blur. Frisk carefully put Flowey (or Asriel. _'God, that_ thing _is the prince?'_ ). Then Sans took the two (now _three)_ of them back to just outside the room of the party. The place had quieted down and some monsters were arranging some sleeping bags and pillows for the monsters to sleep in.

And just as Sans thought, Papyrus ran up to them, asking them where they had been and happily greeting the flower (action that made Sans' eye-socket twitch and flash briefly).

Once everyone in the huge room settled in, the lights went off and everyone drifted off to sleep; all with the excitement of what tomorrow would bring.

* * *

 **Next chapter:**

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( . N:23... please decrypt it and leave me your opinion, I would really appreciate it).


	2. Chapter 1

**Heya! First of all I want to thank every single one of you, _wonderful_ _humans,_ who started following and favorited this story, as well as those of you who left a review and (at least tried) to decrypt the message at the end! :D It was only a Prologue, yet I can see there's a lot of people in both fandoms that already like it! QwQ it makes me so happy!**

 **And about the encrypted message at the end? Well, it was just a small clue for this chapter; clue to their destination and exactly** _who_ **was going with our little human ambassador... It just looked long because I got carried away and I was so excited for this that I ended up writing a poem xD this time I'll just keep it short and simple.** **To decrypt the message at the end of this chapter, search for any** Caesar Cipher tools **and use a rotation number of** 23 **. If you need it, I'll just leave a link at the very end to make things a little easier!**

 **Now, if no one has any _bones to pick with me_ , let's go on with the story!**

"Normal dialog"  
 _'Someone's thoughts'_

* * *

 **Chapter 1:** _ **"Welcome to Gravity Falls"**_

Last time, this nameless narrator mentioned you of a town named Ebott. This place, of course, was mostly known for the tourists to be at the base of the enigmatic Mt. Ebott. While most of the populace of the world ceased to believe the stories of the monsters that once lived among their race, there are still some individuals around the globe that take seriousness on the old legends (especially considering that whoever climbs the mountain never comes back).

But let's take this story to the _other_ and more remote side of the mountain; a small yet extensive location, surrounded by a big forest and high cliffs. A town just West of Weird, slightly East of Eerie and always North of Normal…

 _Gravity Falls_.

Of course such a mysterious place would be located near the other side of the strange mountain!

This unique place has gone through a _lot_ of interesting events. Just a year ago, the very fabric of reality was torn apart in Gravity Falls; thankfully, a barrier (not unlike the one around Mt. Ebott) prevented the _weirdness_ from covering the rest of the world. And just day or two ago, everyone heard what sounded like glass breaking, followed by a slight tremble beneath their feet. Other than that, there wasn't anything out of the ordinary.

If you ever visit Gravity Falls, you will _definitely_ meet some interesting people while you're there. From people like the Corduroys (a family of lumberjacks composed mainly by males –with the exception of Wendy, the oldest daughter), Lazy Susan (a great cook at Greasy's Diner)… heck, even Tad Strange is an interesting guy to have a conversation with! After everything that happened last year, everyone in Gravity Falls took their time to recover. Over time, things in the unique little town went back to normal… or well, as normal as it can get when you live in Gravity Falls.

Yet there was one group of people whose scars remain deep: the Pines.

Stanley Pines' memory took longer to fully recover, and when it did, the nightmares of what happened grew more frequent. Him and Stanford continued to travel around the world, looking for any anomalies to deal with. While they're gone, Jesus "Soos" Altamirano takes care of the Mystery Shack along with his fiancé Melody (and of course, his _abuelita_ visits every now and then to see how he's doing). The 'Mystery twins' –or well, the _younger_ ones?... their parents (after both Mabel and Dipper begged and used their puppy stare on them) let their children take the next bus to Gravity Falls, Oregon.

Just in time, too, because both Stan's got back to the dear shack.

Soos was dusting off Stan's statue on the back; the Mystery Shack was closed for the day and Melody went out to buy some groceries. Everything was calm and quiet while he dusted off the statue's fez, when suddenly…

"Hey, Soos!" came a muffled voice, startling the new Mystery Man.

"Mr. Pines, is that you?!" Soos asked, face going from shock to horror. "Oh no… you are trapped inside the statue!" he went to the back of the counter.

"Wait, what? Soos, what are you talking ab-"

"Don't worry, Mr. Pines. I'll get you outta there!" Soos lifted a big hammer and was about to hit the statue.

"Soos, just open up the door already!" Stan knocked loudly on the door, stopping Soos in his movements.

"Mr. Pines?" he turned to the front of the shack and opened the door. "Mr. Pines, _both_ of you!" he hugged both Stans tightly.

"Yes Soos, we missed you too" choked out Stanley.

"Now, could you please release us and let us pass? We haven't eaten anything in at least two days and there's something important we need to discuss" said Ford, breathing with more ease than Stan at the moment.

"Oh, is that why you came back sooner?" Soos asks, finally letting both men breathe properly.

"Yes, indeed"

After letting both grown men in and serving them both a glass of water, they all sat down in the dining room while both Stans explained their return.

"I've kept contact with Fiddleford in case anything happened" Ford confirmed.

"Apparently, he caught some strange readings in one of his tech-y gadgets" Stan continued, not so much help with the little knowledge he had on the matter. "That, and hearing the sound of a giant glass window or something breaking"

"We wanted to make sure it didn't have anything to do with _that thing_ , so we came to check it out" the genius twin finished.

"Oh, _that_!" Soos exclaimed. "A couple of days ago, everyone heard glass breaking, but we didn't see anything. Whatever it was, sounded like it echoed from Mt. Ebott nearby" Ford spit his water all over his brother (who was about to yell angrily at him).

" _The_ Mount Ebott?!" he asked in shock.

"Um, yeah, we're sure" Soos said, confused on the sudden shock over the scientist's features.

"Why is that place so important, anyway?" Stan asked, drying himself off with some tissues.

"Old legends tell of a war; one that waged between humans and monsters _centuries_ ago" Ford starts with a serious face. "It's said that it took place at the other side of Mt. Ebott. Some of the creatures were able to flee and found safety in this area; but the rest of them weren't so lucky…" he sighed. "Seven mages sealed the monsters under the mountain, cloaking it with a powerful barrier that would only break with the power of seven human souls-"

"Wait, don't you mean the barrier keeping the weirdness in this town?" Stan interrupts.

"No. While it _is_ of a similar power, these barriers are different from each other" the six fingered explained, then continued. "If the barrier surrounding Mt. Ebott is broken –as I can assume for the glass-breaking sound- it means a very powerful soul broke it… or…" he ran a hand across his face and took a deep breath. "The monsters collected the seven human souls they needed. Either way, it means the monsters in the underground are free and, if my current theory is correct, they are most likely heading to this town"

Silence filled the room until Soos broke it.

"But- I mean… the monsters and creatures here are mostly friendly, so maybe the Underground ones aren't so bad?"

"I'm not sure of that, but… I suppose giving them a chance wouldn't be so bad" Ford concluded.

"As long as they don't try to take over the world or touch the merchandise, all is good with me!" Stan finished the conversation, taking the last gulp of water from his glass before getting up and heading to the living room. "Now if you'll excuse, I need to be caught up with the TV shows I've missed!" with that, Ford and Soos stood up and went to the front.

"Friendly monsters or not, we need to get prepared for anything that may happen" Ford took out a new journal from his coat and started writing some things down. "I need to get some things to reinforce the shield around the shack, and get the metal plate in my head checked for any dents…" the author of the journal murmured to himself while he paced around the place.

Soos just smiled and hummed a tune to himself while he went out to clean the front.

"Soos?" he heard not too far from him. He looked up slowly, his eyes trailing a pair of figures with one or two bags of luggage each and a small pig at one's side.

"Dudes?" Soos started, surprised and happy.

"Soos!" they both ran to him and he hugged them tightly.

"Dipper, Mabel! I'm so happy to see you!" Soos could almost cry of happiness. Out of all the things that have happened the whole year, he missed these two so much.

"We missed you guys so much!" Mabel sniffed.

"Yeah, we didn't know if our parents were going to let us stay for this summer!" Dipper continued. "But after some persuasion, they said it was okay" he smiled.

"Well, don't worry, dude and dudette! You know you're always welcome here" Soos smiled at the twins. "I'll just have to tell Melody you guys are staying for the summer; might as well get back with _abuelita_ now that everyone's here!"

"'Everyone'?" the two early teens questioned.

"Don't worry about it. Get it, get in!" he helped them with their bags and gave Waddles a left-over donut from the counter.

Dipper sighed. "It's just as I remembered..."

"Yeah, even gum stuck to the ceiling!" Mabel pointed out, and indeed a piece of bubble gum was stuck to the ceiling… how it even got there, no one really knows…

"Hey Soos, I heard voices! Is everything okay?" Stan shouted from the living room.

"Grunkle Stan?!" both siblings shouted.

Stan's face peeked from the door-frame.

"Kids?!"

"Grunkle Stan!" the twins ran to the arms of their great uncle, all of them with tears threatening to spill out.

"You kids are so annoying…" Stan sniffed. "I missed you both so much!"

"Stan? Are the kids here?!" Ford called out from the back and a smile grew on his face when he saw the twins there. "Dipper, Mabel! I'm so glad to see you so soon" Ford greeted and briefly hugged both.

"Why did you come back so early from your trip?" Dipper asked them.

Ford and Stan shared a serious glance; a wordless discussion between them. They led the kids to the living room and Ford quickly updated them of the situation –of course, he avoided touching the subject of the human souls. Still, he let them know that they may or may not be hostile, so they should be prepared for the worst.

"Whoa…" was all Dipper could say. _'We just came back, and I already have a lot to process here…'_

"Yeah…" Mabel breathed. "… oh! Do you think I can be friends with one of them? Ooohhh, what if someone likes sweaters?! Oh, we could _totally_ become sweater buddies!" she rambled on, making Dipper and Stan crack a smile.

Ford chuckled and headed back to his basement lab (Soos couldn't bring himself to get rid of Ford's gadgets and experiments down there). He took some notes on stuff he needed to get and the necessary measures they should take in cases of emergency.

He enjoyed the peace and quiet (even though he could hear Dipper and Mabel laughing at something and Stan's groan of displeasure), but it all broke when Fiddleford knocked loudly on the door.

"Open up! This is urgent; I need to speak with Stanford _right now_!" Stan let him in and McGucket almost ran in, panting and sweating like he was running for his life.

"Old man McGucket?!" Dipper was shocked. "Are you okay?"

"Yeah, what happened?!" Mabel asked, now concerned for the old man.

"I need – _pant_ \- to speak – _huff_ \- with Stanford" he said breathlessly, holding a hand to his chest and calming down for a bit.

"Fiddleford!" the old twin of science greeted him, surprised at seeing his old friend so soon. "This is a real surprise. What brings you here?"

"I installed some cameras around the area of Gravity Falls" he began, finally getting his bearings. "While some are kept within the populated area, I also added cameras to other parts like the forest, the cliffs and areas near the mountain" he got out his trusty laptop and showed a recording to everyone in the room. "I was just watching it from the corner of my eye this morning, when I noticed _this_!" he pointed to a point of the screen; a blur of at least five different beings getting out of the mountain area and walking in the direction of the town. The recording looked blurry, so no one could really make out what they looked like; but they could clearly see one of them turning to the camera, with bright orbs staring right at them.

"Hey, Ford… do you think _this_ is what we were talking about earlier?" Stan asked, a bit of worry in his eyes as he looked at his brother's shocked expression.

"It might be…" Ford began. "There's an 85% chance it _is_ what we spoke about"

"Does it mean…" Mabel started.

"Are those… the monsters you told us about?!" Dipper finished.

* * *

' _we're being watched'_. That's what was going on in his mind at that moment. He knew this feeling very well; it's the same he had when Alphys first installed her cameras around Snowdin.

They had been walking the path of a small town they saw in the distance and he briefly caught sight of light reflections in the tree branches, and so he stared directly at an active one in hopes he got his message across. _'ya won't_ rattle my bones _if that's what you think you'll accomplish…'_

He felt a tug on his sleeve and he looked down at Frisk's worried face.

"Are you okay?" came the quiet question.

"don't worry, kiddo" he ruffled their head. "all's fine, just enjoying the scenery"

Frisk didn't look the least bit convinced, but let it go anyways.

"THE TOWN WE SAW _MUST_ BE CLOSE! I CAN FEEL IT – _IN MY BONES_!" Papyrus said, voice and walk full of excitement.

"heheh. good one, paps" Sans chuckled at his brother's antics.

"Calm down, Papyrus" Asgore laughed heartily. "We must first try our best to give the humans a good impression"

"Ha! You worry too much, Your Majesty" Undyne said, voice brimming with confidence. " _Of course_ we'll give a good first impression; we are the best monsters those punks will ever meet!"

"I-I just hope they're nice…" Alphys confessed shyly.

"Why wouldn't they be nice to someone as cute as you?!" Undyne hugged her with one arm and gave her a peck on her cheek. Alphys' face turned completely red and everyone laughed along with those two.

The group of seven (and a plant) heard rustling from the bushes on their left. Sans, Asgore, Toriel and Undyne became alert while they pushed the remaining members of the group behind them.

They all held their breath, waiting and waiting until… from the bushes came out… _'a manotaur?'_ Sans was really confused now, and it seemed he wasn't the only one. _'the history books i've read mentioned manotaurs as some of the only monsters to flee from the war, but then_ why _are they here?'_

"Wow, calm down! The smell of a familiar friend brought me here, I'm not going to hurt anyone –unless you want to, but still!"

Everyone dropped their defensive stances and Asgore had a look of recognition.

"Wait a second… I know that voice!" the king exclaimed. "Chutzpar?"

The manotaur took a closer look and then it dawned on him.

"Asgore?! Your Majesty!" the patted the goat dad's back with a friendly gleam in his eyes. "I'm so glad to see you and the queen back on the surface! I get it you found a way to break the barrier?"

"Actually, it was Frisk here who saved us all" he gestured to the human child in their group. Frisk gave a small wave and smiled.

Chutzpar chuckled. "So I see. My king, if there's anything me and my kind I can do for you, just ask away"

"Now that you mention it, we need someone to guide us towards the closest village.

"Oh, you mean Gravity Falls! I know some of the humans there, actually. I'll show you the way-"

"Excellent-"

" _But_ I must test the human! Test their strength!"

Frisk smiled, knowing _just_ the thing that would do. They flexed harder and harder, until Chutzpar was sent flying to a tree.

"Whoa! You are stronger than you look…" he said, quite proud of the results. "Let us go, then. I'm not entirely sure where the town itself is, but I know where you can start looking!"

The group from the underground exchanged looks, before following their new acquaintance. They walked for a long while until they saw the end of the forest; by then, the sun had already set down in the horizon. When they got to the clearing, they could see a small shack illuminated by moonlight.

" _Mystery Shack"_ read a big sign at the top of the shack, the slightly fallen _S_ making it read as _"Hack"_.

"There it is!" Chutzpar told them. "You should just knock on the door and wait a bit for them to just… _react_. They know the weirdness of this town better than anyone, and that's a given considering all that's happened last year" he explained, getting confused and curious looks from everyone else. "Anyway…" he extended his arms in a welcoming manner.

" _Welcome to Gravity Falls!"_

* * *

 **I hope nobody has a problem with me writing Pap's dialogs in all caps x.x I can't change fonts here, so using all lowercase for Sans and ALL CAPS for Papyrus is my way to differentiate them (I mean, Pap's is already known in-game for being very loud and his dialog boxes are all in caps soooo yeah, it seemed logical for me).**

 **Anyways, I hope you all liked it! I didn't plan it to be _so_ long, but I suppose that's a good thing, right? Regardless, thanks for reading! And (if you haven't already), please Follow this story, Favorite if you liked it and leave a Review to tell me what you thought. Positive feedback and small suggestions are always welcomed! :D**

 _ **Next Chapter:**_  
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** **XOB QEBV COFBKAP LO CLBP? QL DFSB JBOZV LO KLQ...**

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decrypt in: rumkin tools/ cipher/caesar . php  (N: 23)


	3. Chapter 2

**Heya, wonderful humans and creatures galore! :D I added "creatures galore" because apparently at least one reader is half monster xD (I'm still waiting for that explanation, by the way!). Anyways, I'm really proud of how this story is turning out! I'm not taking too long with each chapter, rather about a week to publish/finish each OwO seriously, my other two stories I can barely update once every few months or so... And I'm having _so much fun_ writing this, I kid you not! And I'm also so happy that a lot of people like it already! QwQ thank you guys so much, your reviews, follows, and favorites all make my days brighter~!**

 **I've revised this chapter specifically as best as I could, being this is the longest I've written thus far (AROUND 4,000 WORDS?! WTF?!). If you find any errors or any wording wrong, please don't hesitate to tell me -English isn't my birth language so sometimes it's a bit difficult for me to not make any mistakes... either that or I have weird tendencies while writing dialogs. By the way, thanks to the person who pointed my lack of " . " in the dialogs! Usually I don't use them, but I think I should really do it form now on! n.n and I'm glad I haven't seen any complaints on having Papyrus talk LIKE THIS!... and Sans doin' his thing. And I know some people have been hyped since they decrypted the last chapter's message; don't worry, I did a little thing here and I promise for the next chapter you'll read the rest! :D**

 **Again, thanks to anyone who has enjoyed this story so far! And if you have any trouble with decrypting the code, I'll leave a link bellow directly to the cipher and give the number (it's still gonna be the same cipher and number for a while, to avoid any confusion). Now enjoy~!**

Normal narration.  
"Normal dialog."  
 _'Character's thoughts.'_

 _ **Dream sequence  
"Dialog"  
**_ **'Thoughts'**

* * *

 **Chapter 2:** _ **"Friend or foe?"**_

It was around 1 AM. Soos had long gone back to his grandmother's house with Melody, leaving the Pines to assert themselves back in their respective places. Dipper and Mabel prepared their stuff in their attic room; Stan kept the Master Bedroom while Ford made accommodations to get comfortable in his lab. They all slept peacefully for their first night back in Gravity Falls, when…

 _Knock, knock, knock._

The sound echoed through the whole shack and alerted everyone (minus Mabel, who was sleeping like a log) that someone was at the door.

' _Ugh, who's crazy enough to come here at 1 AM?!'_ Dipper thought grumpily, running a hand down his face while sitting in his bed. He was merely staring at Mabel, contemplating whether to go downstairs and see who (or _what_ ) is knocking… _or_ going back to a peaceful sleep –an idea he really liked and decided to do.

And so, Dipper settled back down, even after hearing another loud knock. Mabel's light snores just helped to lull him back to sleep, ready to greet the Wendy he was dating in his dream.

Stan walked down the stairs, grumbling to himself about how his good sleep was interrupted so suddenly. Ford had also gotten out of his lab/room; not murmuring angrily like his brother, but with a simple groan of displeasure.

Stan saw him coming and waved his hand in a dismissive way.

"I got this…" he murmured and answered the door. "Do you have any idea how late it is?!" he yelled, rubbing his eyes sleepily. "We're _closed_ right now, so I why don't you go…" his voice trailed off and his eyes widened slightly at the sight of a small kid in front of the door. "… away…" he coughed and cleared his throat. "Uh, sorry kid. But it's late and everyone was sleeping so…"

"I'm sorry, sir," came the kid's quiet voice. "But we don't know where else to go."

"Do you need any help?" Ford questioned from behind his brother; he turned on the lights of the room. "How did you get here?"

"Someone said you could help us; he said you would understand our… _situation_." The child said, choosing their words carefully.

"Who sent you here?" Ford asked warily. It was just a kid, but the thought of _him_ sending anyone here set him on edge.

"And what do you mean 'us'? Who's here with you?" Stan demanded.

"Well…" the brunette kid began. "I'll show you, but _please_ don't freak out, okay? They are really nice, and they would never hurt anyone!"

"Okay, okay! Geez, just show us already!" Stan answered.

"Alright then..." they looked to the side. "Hey mom, guys!" they called out. "It's okay, you can introduce yourselves!" they smiled.

"Finally!" said an impatient, feminine voice.

"Undyne, please be nice!" scolded someone else with a motherly tone.

Footsteps got closer to the door. Stan and Ford exchanged a look before they fully opened the door. The kid came in and after them…

* * *

"HELLO, HUMANS!"

"Holy sh-" Stan stumbled back and fell on his bottom; a tall skeleton had gotten in his face and yelled his greeting before the old man could even react.

"Stanley!" the other yelled with worry. He reached for his magnetic gun, but…

"i wouldn't do that if i were you, buddy." Came a deeper voice from behind him, startling him and making him turn around. "we don't wanna fight 'ya if we don't have to, ok?" said the grinning (and shorter) skeleton in front of him.

' _How did he even get near me? He was right at the door, behind everyone else!'_

"Grunkle Stan? Grunkle Ford?!" called a worried, female voice from upstairs.

"Is everything okay?!" asked a boy, their voices and footsteps getting closer.

"Kids, don't come in here!"

"What wrong?!" the twins rushed to the room and the sight before them just baffled them.

A tall skeleton wearing an orange-red scarf was standing before their grunkle Stan, a confused expression on his face as he stared at the startled man still sitting on the floor. A shorter skeleton with a blue hoodie was standing close to Ford; the skeleton was grinning, but there was a cautious light in his eye-sockets. A fish-lady in a black tank top was standing protectively in front of a reptile-like woman with a lab-coat; the first holding a spear while the latter looked scared. In the doorway stood two goat-looking creatures (male and female); the male wore regal clothes and a crown atop his head ( _'He must be a king!'_ Mabel concluded to herself) and was holding a flower in a pot ( _'Does that flower have a face?!'_ Dipper thought frantically), while the female in a white and purple tunic hugged a human child close to her. The brunette kid wore a blue and magenta striped sweater, and they looked at everyone else with a concerned expression.

"Whoa, what's going on here?!" Mabel questioned.

"Who are you?!" Dipper demanded warily, holding up the baseball bat that was leaning on the wall.

"Everyone, stop!" shouted two voices, making everyone in the room stare at the child and talking flower.

"Seriously, all of this shouting is annoying me!" grumbled the flower.

"I know this is weird, and they may look intimidating at first…" spoke the little ambassador. "But they are nice."

"We have no desire to harm anyone." Continued the goat man. "So please, just hear us out. Chutzpar, an old friend of mine, showed us the way here and said you might be able to help us."

"Wait, you know Chutzpar? The manotaur?!" Dipper asked in shock, slowly returning the bat to its original place.

The king chuckled, glancing at the young twins at the other side of the room. "Yes, from a time long before the war. Howdy! I am Asgore, king of monsters. It's a pleasure to meet you!" he introduced himself happily, surprising Dipper.

"I'm Toriel, and it's nice to meet all of you." the ex-queen smiled warmly at the human family, making Mabel smile brightly at her.

"Hiya, punks!" the ex-royal captain exclaimed. "The name's Undyne, and whether you like it or not, we're gonna be _besties_!" she grinned widely and looked at the scientist behind her. "Come on, hun! Introduce yourself."

"H-hi there…" the reptile fidgeted in her spot (now shoulder-to-hip with Undyne). "M-my name is Alphys! It's-um… I mean, I-I'm glad I- it's really nice to meet you!" she stammered quickly, making some of the monsters chuckle and her partner hug her tightly.

"Don't be so shy, Alphie! These guys seem fine!" She laughed.

"HELLO, HUMANS!" greeted the tall skeleton. "I AM THE _GREAT_ PAPYRUS! I'M SURE YOU'RE PLEASED TO MEET ME AND MY FRIENDS –hopefully- AND I HOPE WE CAN ALL BE GOOD FRIENDS!" he grinned with a childish light in his features.

The shorter skeleton grinned at his tall brother and looked back at the man he had scared earlier.

"heya. i'm sans." The glowing small orbs in his sockets dimmed slightly ( _'does he feel guilty?')._ "i'm sorry 'bout earlier; didn't mean to scare 'ya too much."

Ford smiled awkwardly. "No, it's fine. I might have overreacted."

"heh, no prob." Sans chuckled, extending his hand. "let's just shake on it."

"I –uh…" Ford hesitated, a small flashback of a horrendous deal coming back to haunt him; but he covered it up with a forced smile ( _'This situation is too delicate to mess it up…'_ ). "Sure thing." He slowly lifted his hand to meet the skeleton's when all of a sudden…

 _Pfffffffffffft._

The fart noise echoed in the entire room and everything got quiet… until most of the people in the room started laughing (except Ford, who at first was just shocked and managed to crack a smile; Dipper cringed, while Papyrus just groaned in annoyance).

"heheh. the ol' 'whoopee cushion in the hand' trick. always a good one."

"SANS, NOW THE HUMANS WON'T BE OUR FRIENDS!" Papyrus basically shrieked at his brother.

"aw come on, paps. you gotta admit that was pretty _humerus_ " Toriel howled with laughter and Papyrus just yelled at his brother.

"Now, then," Toriel began when she had finally calmed down. "why don't you introduce yourself, dear?" she gave her human child a small push.

"I'm Frisk, the _now_ ambassador of monsters" the kid –Frisk- smiled and gestured to the flower. "And this is Flowey. It's nice to meet you!" Flowey just murmured something about not wanting to be with so many people.

"Well, I'm Stanley Pines, and this is my nerd brother Stanford" the grunkle said and gestured to Ford.

"Hi, I'm Mabel!" she waved happily at everyone. "And this, right here, is my bro-bro Dip-stick!" she said, lightly punching her twin's arm.

The boy rubbed his arm and smiled nervously at their guests. "It's _Dipper_ , actually. And it's –uh- nice to meet you, too."

Mabel gasped, drawing her bro's attention. "Oh my god, I _love_ your sweater!" she exclaimed, gesturing to Frisk's outfit. "Oh yes, we can be _sweater buddies_! Do you wanna be my sweater buddy?! Please say yeeeeeess~!" she looked brightly to the monster ambassador.

Frisk took a moment to process her speech and gave her a thumbs up and a smile.

"I would like that!" came their happy response.

"Aw yes!" Mabel fist pumped.

"Now, now, everyone." The king began. "I believe there are most pressing matters to discuss."

"Right." Ford agreed. "Dipper, Mabel, could you both please go for some chairs?"

"Sure, we'll be right back!" Dipper and Mabel went to the kitchen.

"Oh, you really shouldn't bother." Toriel rushed to say.

"It's fine." Mumbled Stan.

"We don't have enough chairs for everyone, but once you've all gotten comfortable, we'll discuss the matter at hand." Ford cleared.

* * *

The kids returned soon enough with four chairs from the kitchen. Alphys sat down in one of the chairs; Toriel sat in another with Frisk sitting in her lap and Flowey in the human's hands; Papyrus refused a chair, so Sans accepted it. One chair was left, and Dipper noticed Stanley rubbing his backside.

"Grunkle Stan, do you need to sit down?" he asked, worried.

"Yea sure, I don't see why not." He took his seat and sighed relieved.

"Now that we're all here, would anyone like to start explaining from the beginning?"

"Yes, of course!" Asgore began. "You see… it all started centuries ago –over half a millennia, if I'm not mistaken… us monsters lived peacefully on the surface along with the human race. Of course, to appease de needs of most of our kind, it was decided that us monsters would stay near mountains and water bodies.

One day... the humans –for reasons unknown even now- declared war against us. Naturally, that battle wasn't fair at all."

"The humans overpowered us easily." Continued the goat mother, hugging her children close. "We monsters may have our own magic abilities, but a human's _soul_ is enough to match a thousand monster souls combined. Besides, unlike a human's soul that can linger even after death, _our_ souls don't last longer after being turned to dust."

Dipper noticed the way Frisk stiffened at that part, but decided to ask at a better moment.

"As I was saying, the humans outmatched us. We were defeated and forced to retreat to the caves under the mountain for safety. Seven mages created an unbreakable barrier that kept us inside." Asgore explained. "Of course, some of us were able to flee to the other side of the mountain and continue existing on the surface."

"namely, they took cover in these areas." Sans added and for the first time since they got here, he looked mildly serious. "and the rest of us? we had to cope with being locked inside the mountain, and made it alright with the resources we could find." He then shrugged. "o' course, i didn't live through the time the war waged; but i've heard and read the stories."

"To break the barrier, we needed a powerful source of energy that could outmatch the mages'."

Sans glanced at Ford's clenched fists.

"guess you've heard the stories, huh?" Ford nodded slowly. "so you know what he's talkin' about." It wasn't a question, Ford noticed.

"The power of _seven human souls_." Silence fell in the whole room. Dipper and Mabel looked shocked, the first immediately glanced at their guests warily and took a step in front of Mabel.

"Is that true?" he asked.

Asgore looked down in shame. "Indeed. I have done many horrible things just to give back hope to my people, and all of it is something I deeply regret." He said seriously. "I understand if you don't accept me here…" he looked up with sad eyes. "but please, my people need a second chance at life on the surface."

"Please, the whole Underground is counting on us!" Frisk begged.

Both Stans were looking down, without saying anything. They have both done awful things –each with a different purpose- and they know perfectly well how such regret felt like. Stanford had made a deal with Bill to gain more knowledge, while Stanley did many (illegal) deeds to get by and for 30 years he lived with the regret of pushing his brother to what could've been his demise. They both made their decision and hoped the kids would agree without any objections.

"We'll help you." they said at the same time.

Asgore looked surprised. "What?"

"We'll help you and the rest of your people, as long as you don't hurt anyone." Ford said.

"Just tell us what you need." Stan finished for his brother.

"Directions to the town itself, and to talk with whoever is in charge here." Frisk said, a proof of how mature they were for their age. "We need to talk to them for living and job arrangements and to evade any problems against the races." Toriel looked down at the child, a look of motherly pride lighting her features.

"And once that's taken care of, I'll go back to the Underground and tell the news to the rest of us." Asgore concluded.

"Sounds fair to me." Shrugged Stan.

Toriel looked down at Frisk tugging her sleeves. "Hm? What is it, my child? Do you want to say something?" Frisk nodded. "Go ahead, then."

"Thanks." They said when they noticed everyone was going to pay attention. "Thing is… I ran away from the place I grew up in. That's actually why I climbed Mt. Ebott in the first place. I grew up in an orphanage, and most kids were mean to me; so I decided to hide in a place no one would dare to look.

I didn't really plan on tripping down to a cave underneath the mountain, but I did. A flower bed softened my fall, but the scare still made me faint mid-fall. When I woke up, I was underground; there was no way back up, so I had to go look somewhere else. In the next room, I encountered _someone._ " Flowey stiffened. "They tried to hurt me, saying it was 'kill or be killed', but mom saved me!" Frisk smiled at Toriel and Flowey relaxed.

"On my way through the Underground, I spared every monster I encountered; whether it was by saying a simple compliment or flirting with them." Frisk giggled at the memory. "I befriended everyone, even those who were supposed to take my soul." Undyne grinned and ruffled the human's hair.

"In the end, I had to fight Asgore." The king flinched. "The good thing is, everyone came to support me and stop the fight. Then after a fight with someone else, _he_ became my friend, and…" they took a deep breath. "he used the 6 human souls and the soul of every monster to break the barrier;" The ambassador smiled sadly. "but that also meant he wouldn't be himself anymore. I want to help him be back to his old self again, and I want every monster to be happy, too!"

"We understand perfectly." Ford smiled. "Tomorrow, we'll show you to the mayor's mansion, and from then you can decide what to do. Given the situation, I suggest the king and your ambassador to talk to him first. Other than the possible scare he'll have at first, Mayor Tyler is a nice man and I'm sure he'll understand."

"Very well, tomorrow it is!" Asgore smiled.

"B-but the only problem r-right now…" Alphys interrupted. "Where are we going to sleep?"

"Well, uh…" Stanley spoke up. "Do any of you have a problem with sleeping on the floor? I think there were some sleeping bags and spare covers somewhere…"

"nah, i can sleep anywhere." Sans confessed with a shrug.

"Usually, I would be against the idea of not sleeping in a bed…" Papyrus murmured. "BUT I, THE GREAT SLEEPER –and early riser- PAPYRUS, WILL GLADLY SLEEP WITH YOUR ACOMMODATIONS!"

"Oh, oh!" Mabel enthusiastically raised her hand.

Ford sighed. "Yes, Mabel? Do you have any ideas?"

"Can some of you guys sleep in our room? Pretty pleeeaaaase?!" she gave the monsters the puppy eyes. "It would be like a slumber party! And we could have a pillow fight, and do other stuff together, pretty pleeeeaaaaaasse~?!"

Frisk was the first to answer with a big smile. "Sure, I would love to!"

"Wait a moment…" Undyne starts. "Did you say… 'fight'? A pillow fight? You wanna fight us?!"

"No, Undyne!" Frisk giggles. "A pillow fight is like a friendly spar. It's just a game, no one really gets hurt! We just throw pillows at each other." They explained.

"Huh…" Undyne thought deeply… before her expression broke in a huge, enthusiastic grin. "That's sounds awesome! Let's do that! Hey Alphie, you coming?"

"I-I'm not sure…" she answered nervously. "I'm not good with s-sleeping with others a-and I'm not good at throwing pillows…"

"Aw, come on, Alphys!" Mabel encouraged her. "It'll be _fun_! Plus, Dipper isn't good at pillow fights either" she snickered when the boy in question stammered.

"T-that's _absolutely not true_! I'm really good at pillow f-fights…" he blushed in embarrassment. "In fact, _I'll_ prove it now!"

"Is that a challenge, punk?" Undyne grinned, brimming with confidence. "Get ready to _lose_!"

"Oh, it's _on_!" Mabel fist-bumped Frisk.

"I, PAPYRUS, HAVE DECIDED TO PARTAKE IN YOUR GAME OF PILLOW FIGHTING!" the tall skele-bro declared. "PREPARE FOR YOUR LOSS, NYEHEHE!"

"Let's go, follow me!" Mabel said, dragging Dipper along with her.

Frisk followed them (first leaving Flowey in a table near a window and giving him a good night kiss; of course, the once-prince recoiled and blushed… how he does that when he's a plant, no one knows…). Undyne carried Alphys upstairs, making the poor scientist blush and stutter. Papyrus was about to follow but first turned to look at his brother.

"SANS, ARE YOU COMING?"

"nah, i'm _bone tired_ right now. you go have fun paps, and let me know if 'ya need anything."

"I WILL!" Papyrus smiled and gleefully ran upstairs with the others.

"Well, _now_ that that's settled, I'm going back to my room" Ford smiled tiredly.

"Me too, I need to help Soos tomorrow with restocking." Stan said, walking back to the master bedroom.

"Good night, everyone." Ford bid them.

"Good night to both of you." Toriel smiled. "And again, thank you so much for your help."

"No problem, miss." Stan chuckled and left the room.

A few minutes later, the few remaining people downstairs had settled in their sleeping bags and the male goat was already snoring loudly. Toriel had a calm smile in her face while she dreamt and Flowey was finally calm enough to close himself and breath quietly.

Sans, on the other hand...

* * *

 _Thud._

He heard the sound from upstairs and went to take a look. Sans was wide awake the whole time, being his first night on the surface and already having to deal with strangers set him on edge. Don't get him wrong –they seemed like good people; he was just worried for his brother's wellbeing and how the humans were going to treat him. Not just that, but he felt someone was watching them –someone who wasn't directly interacting with the people in the room. As if someone who didn't belong here was just watching from outside the window or a dark corner. And so, with an eye almost burning, he quietly teleported himself to the top of the stairs, just outside the attic room. He leaned closer to the door and listened…

"Ow! Mabel, don't push me off the bed!"

"Sorry, bro! You were blocking my throw."

"DON'T WORRY, HUMAN NAMED DIPPER. I'LL DEFEND YOU!"

"I'll help, too!"

"Ooohhh, you're messing with the wrong people, 'ya losers!"

"Y-yeah! We'll w-win for sure."

"We're playing in teams? Aw yeah, come here Waddles! The _ultimate pillow fight is oooonn!"_

"NGAAAAAAAAAAAHHHH!"

"NYEEEEEEEEEEEEEEH!"

"AAAAAAAAAAAAAAUUGHHH!"

"SQUEEEE~"

Multiple thuds, battle cries and oinks could be heard clearly through the door. A genuine smile grew on the skeleton's face and he chuckled light-heartedly. _'those kids are something special, all three of them.'_ He mentally mused. _'frisk befriended everyone so easily, then that girl easily brought everyone together and her brother certainly adds something entirely different on their fun.'_

He teleported himself to the roof of the shack; there was a spot near the kids' window, where he could sit down and gaze at the stars for the first time ever.

' _yup, our stay in this town will certainly be interesting'._ Sans smiled again, leaning back to enjoy the whole view. He slowly closed his eye-sockets and let himself fall into a deep slumber without any nightmares…

… oooor so he thought.

* * *

" _ **ow…" Sans said, as if he had fallen rather hard on something. "ugh, what the…" he opened his sockets slowly to greet a dark place. "I... what?" it was all colored in grayscale (and even then, it was hard to see anything in front of him with how dark it was); it was a long corridor lined with many doors at his sides, the one he could see at the end of the hall read**_ **"Bad Memories"** _ **and it glowed an eerie dark red.**_

" _ **wow,**_ **nope!** _ **i'm not gonna deal with that!" and like that, he just turned and walked away. "after all, i'm no photographer; and fear is a dark room where negatives are developed." Sans chuckled at his own joke.**_

" _ **HAHAHAHAH! That was a good one, blue-heart!" a voice echoed throughout the whole space.**_

" _ **huh?" Sans looked quizzically around him.**_ **'where did** _ **that**_ **come from?'**

" _ **Right behind you, bone-sack!" Sans quickly turned around and in front of him saw…**_

' **a flying triangle…?'** _ **the thing was indeed triangular in form; and yellow, a**_ **really bright** _ **yellow. It was using a black top hat, has black arms and legs and a single eye in its… body?... face?... whatever, the only thing that Sans cared about right now, was to watch out for that dark mischievous aura surrounding the being.**_

" _ **Nice to finally meet you, Sans! The name's Bill Cipher, and I'm sure we'll get along**_ **just fine** _ **!"**_

 _And it was at this moment, Sans knew… things would get even more complicated for them._

* * *

 **...oh geez, PLEASE DON'T KILL ME FOR LEAVING IT AT THAT POINT! Sinceriously, the chapter was long enough as it is! And I think this'll keep you hyped for the next one, right? So there ya go! Hope you enjoyed it! Please leave a Review to tell me what you think, Follow this story so you'll know when another chapter comes up, and Favorite if you really want to! Read you next time, wonderful creatures!**

 _ **Next Chapter:**_

 **IFCB XYLSB GRPQ PQXOQBA CLO QEBFO HFKA  
** **CRII LC BKQBOQXFKJBKQ, CLO VLR XKA F  
** **YRQ XP AXKDBO IFKDBOP FK BXOQE XKA JFKA  
** **YBTXOB QEB YBXPQ TFQE GRPQ LKB BV**

(Caesar Cipher, Rotation N. 23). link:  / tools / cipher / 

**And remember, guys:**

 **REALITYISANILLUTION-THEUNIVERSEISAHOLOGRAM-BUYGOLD-BYEEEEEEEE~!**

 **~Ami~**


	4. Chapter 3

***Finally updating this story fills me with DETERMINATION... DETERMINATION TO GET FINISHED WITH THIS SEMESTER ALREADY, GODDAMMIT! So sorry for the small delay, have you ever had those moments in school where your teacher just seem to know when is an awful time to ask for homework and they still do it anyway?... and those times teachers just want it all for the same date? Yeah, that's been these last two weeks at school. Thankfully, I've had enough free time to finish this one! Wow, almost 4,000 words _just of the chapter itself_. I'm quite proud with how this story is going.**

 **A small notice for the code at the very end of this: I won't use Caesar Cipher anymore, given it has brought some confusion to some readers and to me as well to be honest (lol, not kidding). So now, you'll have to use** Attbash Cipher **, which is far more simple! (ABC turns into ZYX). Sooo yeah, there's that thing!**

 **And kudos to the one who recognized the _Insomnia_ scene in the dream sequence last time! I love the comic (I'm following a comic dub by SwiftSky VA, you should totally go check it out if you haven't already). Anyways, I think that's all I have to say for now. Enjoy!**

"Normal dialog."  
 _'Thoughts.'  
 **Dream**_ **sequence** **  
** **"Dialog."  
** ' **Thoughts'**

* * *

 **Chapter 3:** _ **"Early start"**_

A distant rooster's crow could be heard, waking up most of the individuals in the shack. Including the sleepy skeleton sitting in the roof.

"agh!" Sans woke up startled and slid from the roof. "oh sh-" before he could crash on the ground, he stopped himself mid-fall and teleported himself to the living room. There, he fell to the ground on his back. "ow… whatever that was, it sure _rattled my bones_." He chuckled slightly, standing up and rubbing his backside. He noticed Asgore and Toriel missing –the first probably talking with one of the Pines and getting ready to leave soon.

"So you finally decide to show yourself, huh?" he heard the question from behind him and saw Flowey sneering at him. "And don't even pretend that you were here the whole time, I saw you walking up the stairs last night!"

"heh, no need to be like that, buddy." Sans' sockets narrowed on the flower. "i sure slept well, if that's what you're worried about." _'sure, that's a lie; but it's not like i'm gonna tell him that.'_

"Hah! _Me_ , worried for _you_?!" the flower denied arrogantly. "I just think it's amusing, how you always pretend everything's alright and hide the truth from everyone."

"yeah, it _is_ quite funny, isn't it?" the lights in his sockets disappeared and his voice got darker. "'specially coming from _you_ , _your majesty_."

Asriel's shell growled. "Why, you piece of trash-"

"Sans, is that you?" a warm voice called from the kitchen. Toriel peeked her head from the doorway. "Oh, there you are! Glad to see you're awake."

Sans' personality shifted completely. "oh, hey tori! are you cooking somethin'?"

"Oh yes!" she confessed happily. "I'm making breakfast for everyone! It's a small 'thank you' for this family's kindness for letting us stay."

"that's nice." He sniffed (apparently, with Magic everything is possible for a skeleton to do, huh?). "wow, that smells great!"

"Thank you, Sans!" she smiled. "I've put a lot of work into this! Could you please go wake up the kids?"

"ok. i'll be right back." Sans grinned and calmly walked up the stairs and to the attic room.

He knocked the door lightly and opened it slightly.

"hey, kiddos, time to wake up." He said lightly and peeked his head inside. The sight before him warmed his soul.

Dipper, Mabel and Frisk were fast asleep in one of the beds; the twins were hugging the sides of the silent child. His dear brother was huddled up in the other bed, taking the covers all for himself; Alphys was hanging from one side of the bed while Undyne was sprawled on the floor. Sans could hear light snores from the female Pines and the loud ones from Undyne and Paps.

Sans laughed whole-heartily. _´this is heck adorable, but they need to eat already.'_

He knocked again and spoke louder. "hey kids, time to wake up."

He heard some groans of protest and yawns. "heheh, sorry buddies; but tori made breakfast and she doesn't like to be kept waiting."

"Ugh… HUH? WOWIE, SANS! YOU'RE UP EARLY!"

"yup. guess all of your talk 'bout being punctual and stuff has rubbed off on me."

"THIS IS GREAT!" Papyrus' eyes sparkled. "IN NO TIME, YOU AND I WILL GO OUT FOR JOGS EVERY MORNING AND YOU'LL STOP BEING SUCH A LAZYBONES!"

"heh, i wouldn't take it too far, paps." Sans admitted. "anyways, tori is waiting and whatever she cooked smells good."

"She's the best cook ever!" Frisk told them with a bright smile. "Even her pies are the best I've ever had!"

"Oooohhh, she bakes pies?" Mabel's eyes lit up. "I love pies!"

"Mabel, you love anything as long as it has sugar, glitter or cuteness in it." Dipper said with a smile.

"Well, what are we waiting for? Let's eat!" Undyne got up and rushed downstairs, Alphys and Papyrus in toe.

"Come on, Dip!" the twins smiled at each other and ran downstairs. Sans couldn't help but to watch them go.

' _those two are really close, huh? they're kinda like paps and i…'_ he sighed and went downstairs. _'they sure are something special.'_

* * *

The young ones were all sitting at the dinner table, only the grunkles missing (and Frisk, who was currently watering Flowey).

"I hope you're all hungry!" Toriel smiled and served a plate for each.

"OH, GOODIE! LET'S EAT!" Papyrus' sockets lit up with joy.

"Toriel, this looks great!" Mabel complimented.

"Yeah, and I bet it tastes _way_ better than Stan's pancakes." Dipper shivered at the thought.

"I'm glad you all came down to eat." Toriel began. "Especially _you_ , Papyrus! I think you could use some…"

"Why do I get the feeling you're about to-"

"Use some _meat on those bones!_ " Toriel finished. Sans couldn't contain his laughter and the others at least cracked a smile.

"SANS, I BLAME YOU FOR THIS!" Papyrus yelled indignantly.

"hahahahahah, i accept the blame. that was great, tori."

"Hahah, thank you!" Toriel accepted the compliment.

After breakfast, both Stans and Asgore joined them to get ready for the day. Ford would take Frisk and Asgore to see Mayor Tyler; Undyne offered to go with them in case it was needed (even after she had been reassured time and time again that there was no need to worry). Meanwhile, Stan would stay at the shack and wait for Soos to get back and help with the tourists soon to arrive… and he had _just_ the right plan to make this all work…

"HUMAN! WHAT IS IT THAT YOU WANTED ME TO DO?" the younger skeleton asked curiously, excited to be of help.

"I need you to help greet the tourists today!" he explained. "This shack is a place for tourists to come and have a small taste of all the weird stuff that happens in this town. And I think _you_ , Papyrus, would be the perfect guy- _skeleton_ for the job!"

"Hmm…" he looked thoughtful before brightening up. "WOWIE! I'LL BE THE BEST GREETER THOSE HUMANS WILL EVER MEET!"

"I'm sure you'll be! I'm counting on you." He said, patted the skeleton's back and went to open the front door.

Stanley was sweeping the front of the tourist trap, casually humming to himself while he waited for Soos.

"heya."

"JESUS CHRIST!" Stan yelled startled, quickly turning around to see the always-grinning skeleton right next to him. "When- what- _how_ _did you get here so fast_?!" he questioned, holding his chest tightly.

"i've my ways." Sans shrugged. "by the way, i overheard your conv' with my bro. you want him to greet some visitors today, huh?"

"Yeah, what about it?" Stan looked at him, a bit nervous noting the weird tone in the skeleton's voice.

"nothin' much. just wanted to let you know…" the whole world around them darkened and Sans' sockets turned completely dark. " _if anything happens to him while you try to use him as a tourist attraction, you'll be dead where you stand…_ " his voice darkened and suddenly went back to normal along with the rest of the world ( _'Did everything just…_ freeze _for a moment?'_ ). "but hey, i'm not complaining! in fact, i think this'll be a good thing for paps; he needs somethin' to keep him occupied."

"Y-yeah, you're right…" Stan began, unsure of what to say to the death threat and the sudden attitude change. "Well, some people I know will be here soon to open up the shack to the public, so I think you and your friends should think of what to do." He grabbed the broom and headed back inside, pausing at the doorway. "And… the same thing goes to _you_." He said, turning slightly to look at him seriously. "This is the only family I have, so if anything happens to any of them, you'll have _me_ to answer to. You got it, bonehead?"

Sans closed his sockets and chuckled. "yup, i get 'ya."

And so that moment ended and was never spoken about.

* * *

Ford's group went to town and to the Mayor's house to discuss the monsters' situation. Ford had previously talked to Alphys and Asgore about the barrier surrounding the town –unless they find a way to let the monsters out without actually _breaking_ it, they would have to settle in Gravity Falls for now. Before heading out, Frisk approached Sans.

"hm? what is it, kiddo?" he asked curiously. Frisk just gestured to Flowey at the counter. "ah, don't worry 'bout it. the flower won't leave my sight." His eye flashed briefly, making the ex-prince flinch under his gaze.

Frisk merely gave him a thumbs up and a smile before going out.

As for Stan's group…

"Hey, Mr. Pines!" Soos greeted from the door.

"Yo, boss! How's it going?" a female voice greeted from behind the handyman.

Dipper visibly perked up at the sound of that voice.

"Wendy?!"

She peeked her head from behind Soos and waved at the twins.

"Dipper, Mabel! So good to see you're back in town!" Soos let her pass and the mystery twins went to hug her. "Oh! By the way…" she snatched the hat Dipper was wearing and exchanged it for the famous Pine Tree hat. "I figured you'd want that back." She winked at him.

"Haha yeah, thanks!" he smiled awkwardly and blushed (a sight some of the people in the room could easily notice). "How have you been?"

"Ah, you know, the usual." She conversed casually. "Dad's still being a paranoid mess after last year, but I can't really blame him for that." She smiled.

"Yeah, can't blame him either…" Dipper mumbled. "I still have nightmares about that…" a hand ruffled his hair from under his cap.

"Hey, chill out, dude!" Wendy cheered. "You, Mabel and the Stans came back, so let's celebrate that!"

"Uh yeah, about that…" Stan interjected. "You see, there's been some changes around here… pretty big ones, so I suggest you prepare for that –both of you; I don't want anyone fainting right now."

"Alright, don't worry." Wendy chuckled. "Well, what do you want us to see?"

The Pines exchanged nervous glances at each other and gestured to follow them upstairs.

Wendy's and Soos' jaws dropped with the sight of peculiar monsters just hanging out in the twins' room.

A goat woman stroking a golden flower's petal –let's not forget to mention the flower _had a face_ and seemed to enjoy the treatment-; also, a reptile lady twiddling her thumbs and talking with a pair of skeletons. They all stopped what they were doing to glance at their new guests.

"Uh…" was all the red-head could utter. "Hi…?" she lifted her hand in a hesitant greeting.

…

"GREETINGS, TALLER HUMANS!" said first the tall skeleton, making the shorter one chuckle and the goat lady smile. "I AM THE _GREAT_ PAPYRUS, AND IT'S AN ALSO _GREAT_ PLEASURE TO MEET YOU!"

"Yea, uh, same to you." Wendy replied, already getting used to his energetic and loud personality. "Name's Wendy, by the way."

"Hi, I'm Soos!" the man in question said. "Hey, is this the time where one of us faints? 'Cause I'm _so_ into that idea, dudes." He asked, soon going with that idea and falling backwards.

"… U-uhm… i-is he going to b-be okay?" the scientist asked worriedly.

"Yeah, he'll be fine." The teen dismissed.

"Soos is always fine with that!" Mabel agreed.

* * *

Once Soos woke up and introductions were made, both him and Wendy were quite hyped at the situation.

"Wow, this is so cool!" the Corduroy girl breathe.

"Yeah, dudes!" Soos said as well. "I should really start writing a story about this…" he murmured to himself.

"Anyway, they had decided to stay up here until closing hour." Stan said.

"AND I, THE GREAT PAPYRUS, WILL DO MY BEST TO GREET NEW FRIENDS AT THE DOOR!" Papyrus exclaimed, earning a proud and quite happy look from his brother.

"Alright, enough chit-chat! The tourists will arrive at any minute now, so we need to get everything ready." Stan informed and walked out of the room.

"Well, I gotta restock some of the merchandise downstairs. Later, dudes!" Soos said, going after Stan.

"We'll talk later, okay?" Wendy ruffled the twins' hair and went downstairs as well.

"DO NOT WORRY, HUMANS! I'M COMING TOO!" Papyrus announced and was the last one to leave the room.

…

"Soooo…" Dipper trailed off.

"Who wants to take a look at my scrapbook?!" Mabel said.

"I would love that, my child." Toriel smiled.

"I-I don't see w-why not…" stuttered Alphys.

Sans just shrugged and Flowey grumbled something under his breath.

"Yay! Okay, just come over here and I'll be the best narrator ever!" Mabel exclaimed and Waddles oinked with her. "Aw, of course you agree, Waddles!" she hugged her pig and started her narration of their first summer in Gravity Falls.

Of course, Mabel only talked about her special moments of the summer. Because of that, some questions arose about some pictures and notes on the last pages.

"hey, kiddo…" Sans spoke for the first time in those few hours. "what's that yellow thing you drew?" he pointed to the yellow figure in a sloppy drawing of her and her brother fighting that thing. Sans didn't miss the way they both stiffened.

"Uh… that's…" she nervously glanced at her brother, a silent question to which he spoke out loud.

"That's _Bill_." He answered seriously. "Some sort of demon we encountered last year. He had messed with our family quite a few times just last summer and almost brought the end of the world with him." His fists clenched.

"Thankfully, our grunkles thought of a way to stop him before it was too late!" Mabel interjected before things went even darker. "Anyways, he's long gone now, so there's no need to worry about him!"

"Yeah. It's just…" Dipper looked off to the side, already feeling uncomfortable. "It's a topic I would rather not talk about so, let's just leave it at that, okay?" he cracked a smile.

' _huh… "_ long gone" _they say?'_ Sans let out a breath. "good to know. honestly, i couldn't even begin to _hypotenuse_ what would happen if things turned a whole new _triangle_ in our lives as it is." He joked. Dipper cringed, Flowey deadpanned and the others laughed at the puns.

* * *

 _Meanwhile, downstairs..._

Toriel's laughter boomed throughout the entire shack, scaring some customers downstairs.

"Mommy, what was that?" a scared kid asked.

"I don't know, sweetie." The mother answered, equally scared. "Let's get out of here."

Papyrus saw the two of them leave. After some thinking, he _knew_ just who was responsible for all that racket.

"Grr… SANS, STOP PLAGGING THESE HUMANS' LIVES WITH YOUR INCIDENTAL PUNS!"

"sorry bro!" came from upstairs.

' _OF COURSE HE'S NOT SORRY, THAT LAZYBONES…'_ Papyrus thought and continued with his new job.

* * *

When the sunset came around, it was time to close the shop. Everyone came downstairs to join the workers and bid Wendy and Soos goodbye. Poor Papyrus sat tired in a chair.

"WOWIE, MY LEGS ARE HURTING." He sighed and then perked up. "THAT MUST MEAN I'M REALLY GOOD AT MY NEW JOB!"

"heh, 'ya did a great job, paps. i'm proud of 'ya, you deserve a break right now." Sans said in complete honesty. No one missed the way his eyesockets lit up and how his smile looked less forced when he looked up to his brother.

Dipper saw this exchange and smiled. At first, he had been really wary of each and every monster staying here; but over last night's slumber party and the time they spent together today, he decided it wouldn't hurt too much to give them all a chance.

"Hiya, punks! We're back!" came the loud voice of Undyne at the door. Ford opened the door and let her, Frisk and himself inside.

"Undyne!" Alphys went to receive her with a hug. "Y-you're all back." She noticed there was someone missing. "H-hey, where's Asgore?"

"We transported him to Mt. Ebott." Ford answered. "He wanted to get there as soon as possible and give the rest of your people the good news."

"Good news?" Toriel asked. "Does that mean…"

"The Mayor says you're all welcome here!" Frisk ran to their mom and hugged her excitedly.

"WOWIE! HE REALLY SAID THAT?" Papyrus' sockets shone with happiness.

"Yeah! He was a really nice guy; he listened to our full story and we came up with an agreement of sorts!" Undyne grinned.

"Tomorrow, Mayor Tyler will hold a meeting to introduce the monster race to the townsfolk; there, we will discuss job offers and the possibility of building a whole new residential area for your people." Ford explained.

"Why, these are wonderful news!" Toriel expressed.

"Y-yeah." Alphys stuttered, a small smile on her face. "Until w-we figure out what to do with t-the barrier surrounding the town, it w-would be nice to get settled h-here and get along with t-the residents."

"NYEEEHEHEH, WE WILL MAKE LOTS OF NEW FRIENDS!" Papyrus almost squealed, eyesockets glinting with innocent glee. "ISN'T THIS GREAT, BROTHER?"

"huh?" Sans snapped out of his thoughts. "yeah, it's pretty cool." He admitted absent-mindedly.

"This is amazing! Think of all the cool stuff we'll do together now that you're staying in town!" Mabel excitedly rambled on and on about all the things they could do. Everyone else just listened to her, smiling and laughing while they did.

Frisk let out a laugh when they noticed from the corner of their eye that Sans was being awfully quiet.

"hm?" Sans snapped out of his sleepy trance at the feeling of something tugging at his sleeve. He looked down to see Frisk with a troubled expression. "what'up, kid?"

"Are you okay?" they asked quietly.

"heh, sure i am, buddy. don't worry 'bout it." he answered, ruffling the human's hair and grinning when they heard a groan of displeasure as the child tried to comb it back to its original state. "hey, why don't you go play with papy? i heard he had some new puzzle to show you." Frisk hesitated before hugging him and running to the younger skeleton.

Sans looked around to see if anyone was watching him. Once he decided it was safe to do it, he teleported away.

 _Pop!_ He appeared over the couch at the front porch. He sighed and got himself more comfortable, enjoying the distant sounds of the birds chirping and the tranquility it brought. His eyes glanced upwards at the darkening sky; the sunlight was still visible from his spot, but above the orange lining the horizon, stars were sneaking out one by one in the deep blue.

Sans took in the sight and let out a breath in bliss. "How can anyone take this sight for granted? Certainly beats the underground's rocky ceiling…" he smiled for a moment before his grin faded. Last night's event still circling his mind.

* * *

" _ **Nice to finally meet you, Sans! The name's Bill Cipher, and I'm sure we'll get along just fine!"**_

" _ **uh…" Sans was at a loss of words right now.**_ **'what** _ **is**_ **this thing even supposed to be?! this is no regular monster,** _ **that**_ **i know…'** _ **His mental musing was cut short by that thing –Bill- clearing his throat**_ **('does he even have a throat?... then again, i can do that too…').**

" _ **Look, pal, I don't really have much time." The triangular creature said, rubbing his eye in an annoyed manner. "I just came here to have a little chat with you, so let's not waste any second!... and to answer your mental questions: I am a dream demon, and no I don't have a throat, but a being of pure energy like myself can do**_ **lots** _ **of things." He added, putting an emphasis at the word 'lots'.**_

" _ **ooookay then… what did 'ya wanna talk about?" he asked, straight to the point. His sockets narrowed at the mischievous aura that demon was giving off.**_

" **Now** _ **I have your attention! Good." Bill smiled (or at least it appeared so, by the way his eye curved…). "You see, this plane is called the Mindscape. You could say it's a place where everyone's minds connect without really interfering with each other; a physical landscape of the mind, in simpler words." Bill explained, gesturing to their surroundings. "This place is**_ **your** _ **mind –or well, just a part of it anyway."**_

 _ **Sans soaked in this information. "ok, i kind of understand what you're saying…" his sockets looked at the visitor with suspicion. "but if that's the case, what are**_ **you** _ **doing in**_ **my** _ **mind?"**_

" _ **Geesh, kid, relax!" he held up his hands. "I told you, I'm a**_ **dream** _ **demon; that means I can roam this plane of existence freely." He said, eye and voice taking a darker and more serious tone. "Thing is… I used to be stronger. I had**_ **more power** _ **than anyone else; so much power, I could actually get out of this place and move around**_ **your** _ **world!" Bill was starting to turn red from anger, but he somehow controlled it. "But**_ **someone** _ **tricked me and now I'm too weak."**_

" _ **i still don't see why you would've come here, buddy." Sans was getting tired of this guy. He didn't like the way his personality seemed to shift so swiftly from happy, to angry, and now back to being 'friendly'. And oh he certainly didn't like the way this thing's soul radiated darkness.**_

" _ **You see, I'm really weak right now. I need to find a way to get my strength back and as I was going from dream to dream, I thought**_ **you** _ **would be the perfect guy for the job!" Bill gestured to the skeleton standing before him.**_

" _ **So what do you say, Sans? You help me and I'll give you**_ **anything** _ **you want in return!" he extended an arm towards him, his hand lit up in blue flames. "Do we have a deal?" the demon's voice seemed to echo around the hall.**_

 _ **Sans stared at Bill's eye, then he glanced at the extended hand and back at its owner.**_

" _ **heh. sorry, buddy; but i have no reason to make a deal with ya." Sans denied the offer.**_

" **WHAT?!** _ **How can you say something like that?!" Bill shouted. "There**_ **has** _ **to be something,**_ **anything** _ **! Don't you want money, fame, infinite knowledge?!" he rambled angrily, his yellow form turning an angry red.**_

" _ **i have everything i could ever ask for." He admitted. "besides…" his sockets turned completely black. "who's to say you won't try going back on our deal once my part is done? and i just can't trust powerful beings that are dead-set on striking a deal in someone's mind."**_

" _ **You…" Bill suddenly growled. "You IDIOT! DO YOU HAVE**_ **ANY** _ **IDEA HOW HARD IT'S BEEN FOR ME TO FIND A SUITABLE MIND TO INVADE?!" he snapped his fingers and everything around them turned white. "You know what? Fine, have it your way! But when you're ready, I'll come back for you." He warned.**_

" _ **if you try anything funny on me or my friends, you**_ **really** _ **won't like what happens next…" Sans said, eye flashing blue from his left socket.**_

 _ **Bill laughed. "Hahaha! We'll see about that,**_ **Chuckles…** _ **" Bill mentally smirked when he saw Sans flinch at the nickname. "I'll be watching you-" his voice got deep. "ALL OF YOU."**_

 _ **Bill floated backwards to the exit.**_

" _ **And remember: reality is a game! The universe is a save file! Send Temmie to college! Byyeeee~!" and just like that, the triangle flashed out of existence and Sans woke up.**_

* * *

"so the kids dealt with that guy before, huh?" he mused. "whatever they did to get rid of him didn't really work so well, if last night was anything to go by…" he frowned. "i need to talk with them about this; but later, once everything and everyone has settled in…" he sighed and closed his sockets, slowly slipping into a dreamless sleep.

' _it'll be different this time. everything'll be alright and i won't let anything happen to any of them; not this time.'_

* * *

 **Finally got a chance to write that line (Bill's)... I regret nothing.**

 _ **Next Chapter:**_

 **SVIV RG XLNVH, GSV WZDM LU Z MVD WZB** **  
LMV XZM'G IVHG, GIB ZH SV NZB**  
 **ZOO GSV KRVXVH MLD UZOO RMGL KOZXV**  
 **YVDZIV GSV HVVIH UILN Z DSLOV WZIP HKZXV**


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